The specific aims of the proposed research are to study the relationship between cAMP-dependent and independent phosphorylation or ADP-ribosylation of specific proteins in the dog renal brush border or basal-lateral membranes, and alterations in Na+ dependent and Na+ independent solute transport across the membranes. We will study the transports of amino acids. D-glucose, Na+, and phosphate (Pi). Specific phosphorylated and ADP-ribosylated proteins will be identified using SDS-polyacrylamide gel electrophoresis of phosphorylated or ADP-ribosylated membrane suspensions, and solute transport measured by Millipore filtration techniques utilizing membrane vesicles isolated from the brush border (BBMV) or basal-lateral membranes (BLMV) of dog kidneys. We will determine the effects of in vivo manipulations of dogs including administration of cAMP, glucocorticoids, growth hormone (GH), nicotinamide, or parathyroid hormone, (PTH) to intact dogs, induction of chronic renal failure or metabolic acidosis in dogs, parathyroidectomy of dogs and Pi depletion of dogs, on solute transport in membrane vesicles and on phosphorylation and ADP-ribosylation of vesicles. We will perfuse isolated canine kidneys with substances which might be expected to alter renal reabsorption of Pi or other solutes when administered in vivo, and determine the effects of such perfusions on solute transport in membrane vesicles, phosphorylation and ADP-ribosylation of vesicles. We will study the effects of substances which might be expected to regulate the phosphorylation or ADP-ribosylation of specific brush border or basal-lateral membrane proteins on phosphorylation and ADP-ribosylation in isolated renal BBMV and BLMV, and we will study the possible function of an isolated protein or proteins identifiable on autoradiograms of SDS-polyacrylamide gels of canine BBMV suspensions with Mr 62,000 (Band IX), as a Na+ phosphate co-transporter. We believe that these studies are important in that they will provide an understanding of the commonality or lack of commonality of mechanisms by which several stimuli effect changes in the reabsorption of Pi and other solutes by the kidney. In a broader sense they will provide an understanding of the mechanisms by which the transport of solutes across biological membranes is regulated.